1. Field of the Invention
This invention relates to submersible pump installations for wells and to a safety system which maintains the well under control.
2. Description of the Prior Art
In some hydrocarbon producing formations, sufficient reservoir pressure may be present to cause formation fluids to flow to the well surface. However, the hydrocarbon flow resulting from the natural reservoir pressure may be significantly lower than the desired flow. For these types of wells, electrically powered submersible pumps are sometimes installed to achieve the desired hydrocarbon flow rate. Submersible pumps can be used to raise various liquids to the well surface. Examples of prior art submersible pump and safety valve installations are shown in U.S. Pat. Nos. 3,853,430; 4,121,659; 4,128,127; 4,134,454; 4,425,965; and 4,440,221. The present invention is not limited to electrically powered submersible pumps. Examples of downhole jet pumps which can be used with the present invention are disclosed in U.S. Pat. Nos. 4,390,061 and 4,441,861. Other hydraulically powered pumps such as turbine driven pumps may also be used. The preceding patents are incorporated by reference for all purposes within this application.